This disclosure relates to thermoplastic compositions. In particular, the disclosure relates to poly(arylene ether) compositions. It also discloses a covered conductor. The covered conductor has a flexible wall covering and a conductor of a normal or large cross-section area. The covering comprises a poly(arylene ether) compositions. An auto-wire harness assembly comprising the covered conductor and an end-use-equipment comprising the auto-wire harness assembly are also disclosed herein.
Polyvinyl chloride resins have long been used as the coating resin in the covered conductor and cable industry. However, there is mounting concern over the environmental impact of halogenated materials and non-halogenated alternatives are being sought. This search has met with some success in polyethylene compositions however useful polyethylene compositions typically have high levels of inorganic flame retardant that can result in deterioration of some mechanical properties and processability.
Additionally, as electronic devices become increasingly compact in design there is an increasing need for the cables and wires employed as part of these devices and their accessories to be more flexible and durable. Similarly, as the number of electronic components of automotive engines increase there is an increasing need for the wires connecting the electronic components to be flexible and durable over a range of temperatures and after exposure to the various chemicals found in an automotive environment. The covered conductor (as well as the wire harness assembly) used inside a passenger compartment (such as under the roof, under the carpet, behind the instrument panel, inside door frame) and inside the trunk is also trending towards the same direction. In some application cases, coated conductor is used to transfer electrical power to operate moving devices. In these applications a normal to large size conductor is needed. For these normal to large size conductor, in order to enable bundled wire flexibility and or final wire harness flexibility, the insulting coating material needs to be more flexible. So, there is ever increasing desire to use a more flexible covering layer on a conductor with normal and large diameter (or cross-section area). The covered conductor wire still should meet some essential performance requirements. Industrial standards such as ISO 6722 (such as 2002, Dec. 15 revision) may still be used as guidance.
The more flexible insulation wall covering material may pose difficulties when using crosslinked polyethylene. For crosslinked polyethylene the thinner insulation layer thickness may result in shorter thermal life when aged at oven temperatures between 150° C. and 180° C. This limits their thermal rating. The deleterious effects created by these extremely thin wall requirements have been attributed to copper catalyzed degradation, which is widely recognized as a problem in the industry.
It is possible to coat the copper core with, e.g., tin, in order to prevent the copper from contacting the crosslinked polyethylene but the additional cost of the coating material and the coating process are expensive. In addition, some automotive specifications require that the copper conductor be uncoated. It is also possible to add stabilizers, also known as metal deactivators, to the insulation material but it is recognized that stabilizers yield only partial protection for electrical wire having thin wall thicknesses.
Accordingly, there is a need for a thermoplastic composition with excellent mechanical properties and processability, which is important to the durability and cost effectiveness of covered conductors and cables made using the thermoplastic composition.